National Security Agency Explained

Agency Name:National Security Agency
Preceding1:Armed Forces Security Agency
Jurisdiction:United States
Headquarters:Fort Meade, Maryland
Chief1 Name:General Keith B. Alexander, USA
Chief1 Position:Director
Chief2 Name:John C. Inglis
Chief2 Position:Deputy Director
Parent Agency:United States Department of Defense

The National Security Agency (NSA) is a cryptologic intelligence agency of the United States Department of Defense responsible for the collection and analysis of foreign communications and foreign signals intelligence, as well as protecting U.S. government communications and information systems, which involves information security and cryptanalysis/cryptography.

The NSA is directed by at least a lieutenant general or vice admiral. NSA is a key component of the U.S. Intelligence Community, which is headed by the Director of National Intelligence. The Central Security Service is a co-located agency created to coordinate intelligence activities and co-operation between NSA and other U.S. military cryptanalysis agencies. The Director of the National Security Agency serves as the Commander of the United States Cyber Command and Chief of the Central Security Service.[1]

By law, NSA's intelligence gathering is limited to foreign communications, although domestic incidents such as the NSA warrantless surveillance controversy have occurred.


The National Security Agency's predecessor was the Armed Forces Security Agency (AFSA), created on May 20, 1949.[2] This organization was originally established within the U.S. Department of Defense under the command of the Joint Chiefs of Staff. The AFSA was to direct the communications and electronic intelligence activities of the U.S. military intelligence units: the Army Security Agency, the Naval Security Group, and the Air Force Security Service. However, that agency had little power and lacked a centralized coordination mechanism. The creation of NSA resulted from a December 10, 1951, memo sent by Central Intelligence Agency (CIA) Director Walter Bedell Smith to James S. Lay, Executive Secretary of the National Security Council.[3] The memo observed that "control over, and coordination of, the collection and processing of Communications Intelligence had proved ineffective" and recommended a survey of communications intelligence activities. The proposal was approved on December 13, 1951, and the study authorized on December 28, 1951. The report was completed by June 13, 1952. Generally known as the "Brownell Committee Report," after committee chairman Herbert Brownell, it surveyed the history of U.S. communications intelligence activities and suggested the need for a much greater degree of coordination and direction at the national level. As the change in the security agency's name indicated, the role of NSA was extended beyond the armed forces.

The creation of NSA was authorized in a letter written by President Harry S. Truman in June 1952. The agency was formally established through a revision of National Security Council Intelligence Directive (NSCID) 9 on October 24, 1952,[4] and officially came into existence on November 4, 1952. President Truman's letter was itself classified and remained unknown to the public for more than a generation. A brief but vague reference to the NSA first appeared in the United States Government Organization Manual from 1957, which described it as "a separately organized agency within the Department of Defense under the direction, authority, and control of the Secretary of Defense [...] for the performance of highly specialized technical functions in support of the intelligence activities of the United States."[5]

National Cryptologic Memorial

Crews associated with NSA missions have been involved in a number of dangerous and deadly situations. The well known USS Liberty incident in 1967 and USS Pueblo incident in 1968 are a small sample of the losses endured during the Cold War.[6]

The National Security Agency/Central Security Service Cryptologic Memorial honors and remembers the fallen personnel, both military and civilian, of these intelligence missions. It is made of black granite, and has 163 names (as of 2011) carved into it. It is located at NSA headquarters. A tradition of declassifying the stories of the fallen was begun in 2001.[7]

Organizational structure

The National Security Agency is divided into two major missions: the Signals Intelligence Directorate (SID), which produces foreign signals intelligence information, and the Information Assurance Directorate (IAD), which protects U.S. information systems.[8]


Headquarters for the National Security Agency is at Fort George G. Meade, Maryland, about 15miles southwest of Baltimore. The NSA has its own exit off Maryland Route 295 South labeled "NSA Employees Only." The scale of the operations at the NSA is hard to determine from unclassified data; some 18,000 parking spaces are visible in photos of the site. In 2006, the Baltimore Sun reported that the NSA was at risk of electrical overload because of insufficient internal electrical infrastructure at Fort Meade to support the amount of equipment being installed. This problem was apparently recognized in the 1990s but not made a priority, and "now the agency's ability to keep its operations going is threatened."[9] Its secure government communications work has involved the NSA in numerous technology areas, including the design of specialized communications hardware and software, production of dedicated semiconductors (at the Ft. Meade chip fabrication plant), and advanced cryptography research. The agency contracts with the private sector in the fields of research and equipment.

In addition to its Ft. Meade headquarters, the NSA has facilities at the Texas Cryptology Center in San Antonio, Texas; at Fort Gordon, Georgia, and elsewhere.

On January 6, 2011 a groundbreaking ceremony was held to begin construction on the NSA's first Comprehensive National Cyber-security Initiative (CNCI) Data Center; the "Utah Data Center" for short. The USD $1.5 billion data center is being built at Camp Williams, Utah, located 25miles miles south of Salt Lake City. The data center will help support the agency's National Cyber-security Initiative.[10]


NSANet is the official National Security Agency intranet. It is a classified internal network, and TS/SCI. In 2004 it was reported to have used over twenty commercial off-the-shelf operating systems. Some universities that do highly-sensitive research are allowed to connect to it. In 1998 it, along with NIPRNET and SIPRNET, had "significant problems with poor search capabilities, unorganized data and old information". In 2001 it was reported on the PR Newswire that NSA bought Auto-Trol's product KONFIG® NM to help "document and manage" NSANet.[11] [12] [13] [14] [15] [16] [17] [18]

National Computer Security Center

The National Computer Security Center, once part of the National Security Agency, was established in 1981 and was responsible for testing and evaluating computer equipment for use in high security and/or confidential applications. NCSC was also responsible for publishing the Orange Book and Trusted Network Interpretation (Red Book) detailing trusted computing and network platform specifications. The two works are more formally known as the Trusted Computing System Evaluation Criteria and Trusted Network Interpretation, part of the Rainbow Series, however, they have largely been replaced by the Common Criteria.



NSA's eavesdropping mission includes radio broadcasting, both from various organizations and individuals, the Internet, telephone calls, and other intercepted forms of communication. Its secure communications mission includes military, diplomatic, and all other sensitive, confidential or secret government communications. It has been described as the world's largest single employer of mathematicians,[19] and the owner of the single largest group of supercomputers,[20] but it has tried to keep a low profile. For many years, its existence was not acknowledged by the U.S. government, earning it the nickname, "No Such Agency" (NSA). It was also quipped that their motto is "Never Say Anything".[21]

According to the Washington Post, "[e]very day, collection systems at the National Security Agency intercept and store 1.7 billion e-mails, phone calls and other types of communications. The NSA sorts a fraction of those into 70 separate databases."[22]

Because of its listening task, NSA/CSS has been heavily involved in cryptanalytic research, continuing the work of predecessor agencies which had broken many World War II codes and ciphers (see, for instance, Purple, Venona project, and JN-25).

In 2004, NSA Central Security Service and the National Cyber Security Division of the Department of Homeland Security (DHS) agreed to expand NSA Centers of Academic Excellence in Information Assurance Education Program.[23]

As part of the National Security Presidential Directive 54/Homeland Security Presidential Directive 23 (NSPD 54), signed on January 8, 2008 by President Bush, the NSA became the lead agency to monitor and protect all of the federal government's computer networks from cyber-terrorism.[24] In 2010, Robert Gates called for DHS to have a "cell" that would be able to apply the full surveillance powers of NSA for domestic cyber security.[25]


See main article: ECHELON.

NSA/CSS, in combination with the equivalent agencies in the United Kingdom (Government Communications Headquarters), Canada (Communications Security Establishment), Australia (Defence Signals Directorate), and New Zealand (Government Communications Security Bureau), otherwise known as the UKUSA group,[26] is widely reported to be in command of the operation of the so-called ECHELON system. Its capabilities are suspected to include the ability to monitor a large proportion of the world's transmitted civilian telephone, fax and data traffic.

Technically, almost all modern telephone, internet, fax and satellite communications are exploitable due to recent advances in technology and the 'open air' nature of much of the radio communications around the world.NSA's presumed collection operations have generated much criticism, possibly stemming from the assumption that NSA/CSS represents an infringement of Americans' privacy. However, NSA's United States Signals Intelligence Directive 18 (USSID 18) strictly prohibits the interception or collection of information about "... U.S. persons, entities, corporations or organizations...." without explicit written legal permission from the United States Attorney General when the subject is located abroad, or the Foreign Intelligence Surveillance Court when within U.S. Borders.[27] The U.S. Supreme Court has ruled that intelligence agencies cannot conduct surveillance against American citizens. There are a few extreme circumstances where collecting on a U.S. entity is allowed without a USSID 18 waiver, such as with civilian distress signals, or sudden emergencies such as the September 11, 2001 attacks; however, the USA PATRIOT Act has significantly changed privacy legality.

There have been alleged violations of USSID 18 that occurred in violation of NSA's strict charter prohibiting such acts. In addition, alleged ECHELON-related activities, including its use for motives other than its national security, including political and industrial espionage, have received criticism from countries outside the UKUSA alliance.[28] [29] Examples include the gear-less wind turbine technology designed by the German firm Enercon[30] [31] and the speech technology developed by the Belgian firm Lernout & Hauspie. An article in the Baltimore Sun reported in 1995 that aerospace company Airbus lost a $6 billion contract with Saudi Arabia in 1994 after NSA reported that Airbus officials had been bribing Saudi officials to secure the contract.[32] [33]

Domestic activity

NSA's mission, as set forth in Executive Order 12333, is to collect information that constitutes "foreign intelligence or counterintelligence" while not "acquiring information concerning the domestic activities of United States persons". NSA has declared that it relies on the FBI to collect information on foreign intelligence activities within the borders of the USA, while confining its own activities within the USA to the embassies and missions of foreign nations.

NSA's domestic surveillance activities are limited by the requirements imposed by the Fourth Amendment to the U.S. Constitution; however, these protections do not apply to non-U.S. persons located outside of U.S. borders, so the NSA's foreign surveillance efforts are subject to far fewer limitations under U.S. law.[34] The specific requirements for domestic surveillance operations are contained in the Foreign Intelligence Surveillance Act of 1978 (FISA), which does not extend protection to non-U.S. citizens located outside of U.S. territory.[34]

These activities, especially the publicly acknowledged domestic telephone tapping and call database programs, have prompted questions about the extent of the NSA's activities and concerns about threats to privacy and the rule of law.

Wiretapping programs

Domestic wiretapping under Richard Nixon

In the years after President Richard Nixon resigned, there were several investigations of suspected misuse of Central Intelligence Agency (CIA) and NSA facilities. Senator Frank Church headed a Senate investigating committee (the Church Committee) which uncovered previously unknown activity, such as a CIA plot (ordered by President John F. Kennedy) to assassinate Fidel Castro. The investigation also uncovered NSA's wiretaps on targeted American citizens. After the Church Committee hearings, the Foreign Intelligence Surveillance Act of 1978 became law, limiting circumstances under which domestic surveillance was allowed.

IT projects: ThinThread, Trailblazer, Turbulence

NSA created new IT systems to deal with the flood of information from new technologies like the internet and cellphones.

ThinThread contained advanced data mining capabilities. It also had a 'privacy mechanism'; surveillance was stored encrypted; decryption required a warrant. The research done under this program may have contributed to the technology used in later systems. Thinthread was cancelled when Michael Hayden chose Trailblazer, which did not include Thinthread's privacy system.[35]

Trailblazer Project ramped up circa 2000. SAIC, Boeing, CSC, IBM, and Litton worked on it. Some NSA whistleblowers complained internally about major problems surrounding Trailblazer. This led to investigations by Congress and the NSA and DoD Inspectors General. The project was cancelled circa 2003-4; it was late, overbudget, and didn't do what it was supposed to do. The Baltimore Sun ran articles about this in 2006-07. The government then raided the whistleblower's houses. One of them, Thomas Drake, was charged with in 2010, part of Obama's unusual use of espionage law against leakers and whistleblowers.[36] [37]

Turbulence started circa 2005. It was developed in small, inexpensive 'test' pieces rather than one grand plan like Trailblazer. It also included offensive cyber-warfare capabilities, like injecting malware into remote computers. Congress criticized Turbulence in 2007 for having similar bureaucratic problems as Trailblazer.[37]

Warrantless wiretaps under George W. Bush

See main article: NSA warrantless surveillance controversy.

On December 16, 2005, the New York Times reported that, under White House pressure and with an executive order from President George W. Bush, the National Security Agency, in an attempt to thwart terrorism, had been tapping phone calls made to persons outside the country, without obtaining warrants from the United States Foreign Intelligence Surveillance Court, a secret court created for that purpose under the Foreign Intelligence Surveillance Act (FISA).[38]

One such surveillance program, authorized by the U.S. Signals Intelligence Directive 18 of President George Bush, was the Highlander Project undertaken for the National Security Agency by the U.S. Army 513th Military Intelligence Brigade. NSA relayed telephone (including cell phone) conversations obtained from both ground, airborne, and satellite monitoring stations to various U.S. Army Signal Intelligence Officers, including the 201st Military Intelligence Battalion. Conversations of citizens of the U.S. were intercepted, along with those of other nations.[39]

Proponents of the surveillance program claim that the President has executive authority to order such action, arguing that laws such as FISA are overridden by the President's Constitutional powers. In addition, some argued that FISA was implicitly overridden by a subsequent statute, the Authorization for Use of Military Force, although the Supreme Court's ruling in Hamdan v. Rumsfeld deprecates this view. In the August 2006 case ACLU v. NSA, U.S. District Court Judge Anna Diggs Taylor concluded that NSA's warrantless surveillance program was both illegal and unconstitutional. On July 6, 2007 the 6th Circuit Court of Appeals vacated the decision on the grounds that the ACLU lacked standing to bring the suit.[40]

AT&T Internet monitoring

In May 2006, Mark Klein, a former AT&T employee, alleged that his company had cooperated with NSA in installing hardware to monitor network communications including traffic between American citizens.[41]

Wiretapping under Barack Obama

The New York Times reported in 2009 that the NSA is intercepting communications of American citizens including a Congressman, although the Justice Department believed that the NSA had corrected its errors.[42] United States Attorney General Eric Holder resumed the wiretapping according to his understanding of the Foreign Intelligence Surveillance Act of 1978 Amendments Act of 2008 which Congress passed in July 2008 but without explaining what had occurred.[43]

Transaction data mining

NSA is reported to use its computing capability to analyze "transactional" data that it regularly acquires from other government agencies, which gather it under their own jurisdictional authorities. As part of this effort, NSA now monitors huge volumes of records of domestic emails and Internet searches as well as bank transfers, credit-card transactions and travel and telephone records, according to current and former intelligence officials interviewed by the Wall Street Journal.[44]

Role in scientific research and development

NSA has been involved in debates about public policy, both indirectly as a behind-the-scenes adviser to other departments, and directly during and after Vice Admiral Bobby Ray Inman's directorship. NSA was a major player in the debates of the 1990s regarding the export of cryptography. Restrictions on export were reduced but not eliminated in 1996.

Data Encryption Standard

See main article: Data Encryption Standard.

NSA was embroiled in some minor controversy concerning its involvement in the creation of the Data Encryption Standard (DES), a standard and public block cipher algorithm used by the U.S. government and banking community. During the development of DES by IBM in the 1970s, NSA recommended changes to some details of the design. There was suspicion that these changes had weakened the algorithm sufficiently to enable the agency to eavesdrop if required, including speculation that a critical component—the so-called S-boxes—had been altered to insert a "backdoor" and that the reduction in key length might have made it feasible for NSA to discover DES keys using massive computing power. It has since been observed that the S-boxes in DES are particularly resilient against differential cryptanalysis, a technique which was not publicly discovered until the late 1980s, but which was known to the IBM DES team. The United States Senate Select Committee on Intelligence reviewed NSA's involvement, and concluded that while the agency had provided some assistance, it had not tampered with the design.[45] [46] In late 2009 NSA declassified information stating that "NSA worked closely with IBM to strengthen the algorithm against all except brute force attacks and to strengthen substitution tables, called S-boxes. Conversely, NSA tried to convince IBM to reduce the length of the key from 64 to 48 bits. Ultimately they compromised on a 56-bit key."[47]

Clipper chip

See main article: Clipper chip.

Because of concerns that widespread use of strong cryptography would hamper government use of wiretaps, NSA proposed the concept of key escrow in 1993 and introduced the Clipper chip that would offer stronger protection than DES but would allow access to encrypted data by authorized law enforcement officials. The proposal was strongly opposed and key escrow requirements ultimately went nowhere. However, NSA's Fortezza hardware-based encryption cards, created for the Clipper project, are still used within government, and NSA ultimately published the design of the SKIPJACK cipher (but not the key exchange protocol) used on the cards.

Advanced Encryption Standard

See main article: Advanced Encryption Standard.

Possibly because of previous controversy, the involvement of NSA in the selection of a successor to DES, the Advanced Encryption Standard (AES), was initially limited to hardware performance testing (see AES competition). NSA has subsequently certified AES for protection of classified information (for at most two levels, e.g. SECRET information in an unclassified environment) when used in NSA-approved systems.


The widely-used SHA-1 and SHA-2 hash functions were designed by NSA. SHA-1 is a slight modification of the weaker SHA-0 algorithm, also designed by NSA in 1993. This small modification was suggested by NSA two years later, with no justification other than the fact that it provides additional security. An attack for SHA-0 that does not apply to the revised algorithm was indeed found between 1998 and 2005 by academic cryptographers. Because of weaknesses and key length restrictions in SHA-1, NIST deprecates its use for digital signatures, and approves only the newer SHA-2 algorithms for such applications from 2013 on.[48]

A new hash standard, SHA-3, is currently under development. An ongoing competition, closely resembling the successful AES process, will select the function used by the standard and is scheduled to end in 2012.

Dual EC DRBG random number generator

See main article: Dual EC DRBG.

NSA promoted the inclusion of a random number generator called Dual EC DRBG in the U.S. National Institute of Standards and Technology's 2007 guidelines. This led to speculation of a backdoor which would allow NSA access to data encrypted by systems using that random number generator.[49]

Academic research

NSA has invested many millions of dollars in academic research under grant code prefix MDA904, resulting in over 3,000 papers (as of 2007-10-11). NSA/CSS has, at times, attempted to restrict the publication of academic research into cryptography; for example, the Khufu and Khafre block ciphers were voluntarily withheld in response to an NSA request to do so.


NSA has the ability to file for a patent from the U.S. Patent and Trademark Office under gag order. Unlike normal patents, these are not revealed to the public and do not expire. However, if the Patent Office receives an application for an identical patent from a third party, they will reveal NSA's patent and officially grant it to NSA for the full term on that date.[50]

One of NSA's published patents describes a method of geographically locating an individual computer site in an Internet-like network, based on the latency of multiple network connections.[51]


The NSA received criticism early on in 1960 after two agents had defected to the Soviet Union. Investigations by the House Un-American Activities Committee and a special subcommittee of the House Armed Services Committee revealed severe cases of ignorance in personnel security regulations, prompting the former personnel director and the director of security to step down and leading to the adoption of stricter security practices.[5] Nonetheless, security breaches reoccurred only a year later when in an issue of Izvestia of July 23, 1963, a former NSA employee published several cryptologic secrets. The very same day, an NSA clerk-messenger committed suicide as ongoing investigations disclosed that he had sold secret information to the Soviets on a regular basis. The reluctance of Congressional houses to look into these affairs had prompted a journalist to write "If a similar series of tragic blunders occurred in any ordinary agency of Government an aroused public would insist that those responsible be officially censured, demoted, or fired." David Kahn criticized the NSA's tactics of concealing its doings as smug and the Congress' blind faith in the agency's right-doing as shortsighted, and pointed out the necessity of surveillance by the Congress to prevent abuse of power.[5]

The number of exemptions from legal requirements has also been criticized. When in 1964 the Congress was hearing a bill giving the director of the NSA the power to fire at will any employee, the Washington Post wrote: "This is the very definition of arbitrariness. It means that an employee could be discharged and disgraced on the basis of anonymous allegations without the slightest opportunity to defend himself." Yet, the bill was accepted with overwhelming majority.[5]

On January 17, 2006, the Center for Constitutional Rights filed a lawsuit, CCR v. Bush, against the George W. Bush Presidency. The lawsuit challenged the National Security Agency's (NSA's) surveillance of people within the U.S., including the interception of CCR emails without securing a warrant first.[52] [53]


The heraldic insignia of NSA consists of a bald eagle facing its right, grasping a key in its talons, representing NSA's clutch on security as well as the mission to protect and gain access to secrets. The eagle is set on a background of blue and its breast features a blue shield supported by 13 bands of red and white. The surrounding white circular border features "National Security Agency" around the top and "United States of America" underneath, with two five-pointed silver stars between the two phrases. The current NSA insignia has been in use since 1965, when then-Director, LTG Marshall S. Carter (USA) ordered the creation of a device to represent the Agency.[54]

In fiction

See main article: NSA in fiction. Since the existence of the NSA has become more widely known in the past few decades, and particularly since the 1990s, the agency has regularly been portrayed in spy fiction. Many such portrayals grossly exaggerate the organization's involvement in the more sensational activities of intelligence agencies. The agency now plays a role in numerous books, films, television shows, and video games.


See main article: Director of the National Security Agency.


Notable cryptanalysts

NSA encryption systems

See main article: NSA encryption systems.

NSA is responsible for the encryption-related components in these systems:

NSA has specified Suite A and Suite B cryptographic algorithm suites to be used in U.S. government systems; the Suite B algorithms are a subset of those previously specified by NIST and are expected to serve for most information protection purposes, while the Suite A algorithms are secret and are intended for especially high levels of protection.

Some past NSA SIGINT activities

See also

NSA computers

Further reading

External links

Notes and References

  1. Web site: Cybersecurity Discussion with General Keith B. Alexander, Director of the NSA, Commander of U.S. Cyber Command | Center for Strategic and International Studies. 2012-01-13.
  2. Web site: The Origins of the National Security Agency 1940-1952 (U). Burns. Thomas L.. National Security Agency. 2010-08-11.
  3. In a footnote on p. 30 of Body of Secrets (Anchor Books 2002), James Bamford mentions the classified CIA memorandum "Proposed Survey of Intelligence Activities" (December 10, 1951).
  4. Memorandum on Communications Intelligence Activities
  5. David Kahn, The Codebreakers, Scribner Press, 1967, chapter 19, pp. 672–733.
  6. A dangerous business
  7. Web site: National Cryptologic Memorial (List of Names) - NSA/CSS. 2012-01-13.
  8. Web site: The National Security Agency Frequently Asked Questions. National Security Agency. 2010-04-15.
  9. Web site: NSA risking electrical overload. 2006-08-06. Gorman, Siobhan.,0,5137448.story?coll=bal-home-headlines . 2006-08-11.
  10. News: Utah's $1.5 billion cyber-security center under way. Steve Fidel. Deseret News. 6 January 2011. 6 January 2011.
  11. Web site: [ ARC Registration]. National Security Agency. 2009. 2011-04-13. NSA ARC.
  12. Web site: 2009 National Intelligence Consumer's Guide. DNI. 2009. 2011-04-13. Director of National Intelligence.
  13. Web site: Theater Army Operations, Field Manual No. 3-93 (100-7). US Army. 2011-04-13.
  14. Web site: Systems, Network, and Information Integration Context for Software Assurance. Joe Jarzombek. 2004. 2011-04-13. Carnegie Mellon University.
  15. Web site: Dealing with Sensitive Data at Penn State’s Applied Research Laboratory: Approach and Examples. Dr. Christopher Griffin. 2010. 2011-04-13.
  16. Web site: Thesis; Modeling and Simulation of a Global Reachback Architecture.... September 1998. 2011-04-13. Misiewicz.
  17. Web site: Auto-trol Technology Corporation. PR Newswire. 2001-09-25. 2011-04-14.
  18. Web site: press release. 2001-09-25. Auto-Trol /.
  19. Statement for the Record. Harvey A. Davis. Harvey. Davis. 12 March 2002. 342 Dirksen Senate Office Building, Washington, D.C.. 2009-11-24.
  20. News: Rigging the game. Baltimore Sun. December 4, 1995.
  21. News: Bamford, James. The Agency That Could Be Big Brother. December 25, 2005. The New York Times. September 11, 2005.
  22. [Dana Priest|Priest, Dana]
  23. National Security Agency and the U.S. Department of Homeland Security Form New Partnership to Increase National Focus on Cyber Security Education. NSA Public and Media Affairs. 2008-07-04. 2004-04-22.
  24. News: Bush Order Expands Network Monitoring: Intelligence Agencies to Track Intrusions. Ellen Nakashima. The Washington Post. 2008-01-26. 2008-02-09.
  25. "Wall Street Journal CEO Council 2010 Annual Meeting."
  26. Richelson, Jeffrey T.; Ball, Desmond (1985). The Ties That Bind: Intelligence Cooperation Between the UKUSA Countries. London: Allen & Unwin. ISBN 0-04-327092-1
  27. National Security Agency. United States Signals Intelligence Directive 18. National Security Agency July 27, 1993. Last access date March 23, 2007
  28. Web site: European Parliament Report on ECHELON. PDF. 2001. July. 2008-07-04.
  29. Web site: Nicky Hager Appearance before the European Parliament ECHELON Committee. 2001. April. 2008-07-04.
  30. Die Zeit: 40/1999 "Verrat unter Freunden" ("Treachery among friends", German), available at
  31. Report A5-0264/2001 of the European Parliament (English), available at European Parliament website
  32. News: Echelon: Big brother without a cause. 2008-07-04. July 6, 2000. BBC News.
  33. Web site: Interception capabilities 2000. 2008-07-04.
  34. David Alan Jordan. Decrypting the Fourth Amendment: Warrantless NSA Surveillance and the Enhanced Expectation of Privacy Provided by Encrypted Voice over Internet Protocol. Boston College Law Review. May, 2006. Last access date January 23, 2007
  35. News: Siobhan. Gorman. Siobhan Gorman. NSA killed system that sifted phone data legally. Baltimore Sun. Tribune Company (Chicago, IL). 2006-05-17. 2008-03-07. The privacy protections offered by ThinThread were also abandoned in the post–September 11 push by the president for a faster response to terrorism..,1,5386811.story?ctrack=1&cset=true. 2007-09-27.
  36. See refs of Thomas Andrews Drake article
  37. Bamford, Shadow Factory, p 325-340
  38. [James Risen]
  40. 6th Circuit Court of Appeals Decision
  41. 2007. February 16. For Your Eyes Only?. NOW. on PBS
  42. News: Lichtblau, Eric and Risen, James. April 15, 2009. N.S.A.’s Intercepts Exceed Limits Set by Congress. The New York Times. 2009-04-15.
  43. News: Ackerman, Spencer. NSA Revelations Spark Push to Restore FISA. April 16, 2009. The Washington Independent. Center for Independent Media. 2009-04-19.
  44. News: NSA's Domestic Spying Grows As Agency Sweeps Up Data. Siobahn. Gorman. The Wall Street Journal Online. 2008-03-10. 2008-03-17. . 2008-03-13.
  45. Book: Davies, D.W.. W.L. Price. Security for computer networks, 2nd ed.. John Wiley & Sons. 1989.
  46. Robert Sugarman (editor). On foiling computer crime. IEEE Spectrum. July. 1979. IEEE.
  47. Web site: American Cryptology during the Cold War, 1945-1989.Book III: Retrenchment and Reform, 1972-1980, page 232. Thomas R. Johnson. 2010-01-03. NSA, DOCID 3417193 (file released on 2009-12-18, hosted at 2009-12-18.
  48. Draft NIST SP 800-131, June 2010.
  49. News: Did NSA Put a Secret Backdoor in New Encryption Standard?. Bruce Schneier. Wired News. 2007-11-15. 2008-07-04.
  50. Book: Schneier, Bruce. Bruce Schneier

    . Bruce Schneier. Applied Cryptography, Second Edition. John Wiley & Sons. 1996. 609–610. 0-471-11709-9.

  51. Web site: United States Patent and Trademark Office. United States Patent 6,947,978 - Method for geolocating logical network addresses.. 2005-09-20. 2008-07-04.
  52. News: Ex-Guantanamo lawyers sue for recordings of client meetings. May 19, 2007. Mike Rosen-Molina. The Jurist. 2007-05-22. Mike Rosen-Molina.
  53. Web site: CCR v. Bush. Center for Constitutional Rights. June 15, 2009.
  54. Web site: The National Security Agency Insignia. National Security Agency. 2008-07-04.